CHINA: According to research recently published in Nutrients, vitamin D supplementation does not generally reduce the incidence of asthma exacerbations in children, but it does do so in those with low serum 25-hydroxyvitamin D (25[OH]D) concentrations.
Currently, 20% of the world's population is affected by allergic disorders, the most of which are asthma, allergic rhinitis (AR), atopic dermatitis (AD), and food allergies.
In recent decades, allergy illnesses have become more common, particularly in youngsters. Genetic predisposition might account for some of this, but environmental variables like vitamin D deficiency also play a role. Numerous observational studies have revealed a high prevalence of vitamin D insufficiency in children with allergic disorders. It is unclear, though, if vitamin D supplementation can help children with allergic illnesses fare better.
The purpose of the study was to examine the effects of vitamin D (VitD) supplementation on children with allergic disorders. The researchers did this by conducting a systematic review and meta-analysis.
The Cochrane library, MEDLINE, Embase, Web of Science, and three Chinese databases were searched up to August 15, 2022, for this purpose. Children with allergic disorders were included in randomized controlled trials (RCTs) contrasting vitamin D therapy with a placebo. There were 32 RCTs totaling 2347 participants.
Key findings of the study:
Vitamin D supplementation did not lower the risk of asthma exacerbations in children overall when compared with placebo (risk ratio (RR) = 0.84, 95% confidence interval (CI): 0.65 to 1.08, p = 0.18), but it did lower the risk in children whose baseline serum 25(OH)D was less than 10 ng/mL (RR = 0.48, 95% CI: 0.28 to 0.83, p = 0.009).
In comparison to placebo, vitamin D supplementation significantly decreased the Eczema Area and Severity Index scores or the Scoring Atopic Dermatitis scores in children with atopic dermatitis (standard mean difference = 0.5, 95% CI: 0.87 to 0.12, p = 0.009).
Children with allergic rhinitis also had a lower symptom-medication score with vitamin D supplementation compared to placebo (mean (standard deviation): 43.7 (3.3) vs. 57.8 (4.4), p = 0.001).
The authors concluded that the severity of AD and the signs and symptoms of AR in children can be safely decreased with vitamin D supplementation.
Large-scale and carefully planned RCTs are required, according to the authors, "to validate these results and explore the optimal vitamin D regimen and the patients who would benefit most from vitamin D supplementation."
REFERENCE
Li Q, Zhou Q, Zhang G, Tian X, Li Y, Wang Z, Zhao Y, Chen Y, Luo Z. Vitamin D Supplementation and Allergic Diseases during Childhood: A Systematic Review and Meta-Analysis. Nutrients. 2022; 14(19):3947. https://doi.org/10.3390/nu14193947